- Caleffi

Flow switch
CALEFFI
626 series
cert. n° 0003
01052/07 GB
ISO 9001
replaces dp 01052/99
Function
The flow switch detects whether there is any flow in the piping and
opens or closes an electrical contact. It is normally used in heating,
air-conditioning, refrigeration, water treatment, additive pumping
and process systems in general. By means of the flow switch it is
possible: to control devices such as pumps, burners, compressors,
refrigerators, motorized valves; to turn on indicator and alarm
devices and regulate equipments for dosing water additives.
In heating systems, especially, the flow switch has the objective of
switching the burner off in case of a lack of medium circulation
within the water heater circuit. A lack of circulation would otherwise
impair the operation of the temperature-sensitive safety and
protection devices.
Product range
Code 626600 Flow switch
Code 626009 Set of paddles
size 1” M
for pipe diameters from 1” to 8”
Technical specifications
Connection:
Pipe adjustability:
Electric specifications
Voltage:
Current:
Protection class:
Mark:
F
C
E
Performance
Medium:
Max. percentage of glycol:
Max. working pressure:
Medium temperature range:
Max. ambient temperature:
brass EN 12165 CW617N
self-extinguishing polycarbonate
self-extinguishing polycarbonate
stainless steel
stainless steel
stainless steel
EPDM
D
Materials
Body:
Cover:
Microswitch protection casing:
Bellows rod and bellows:
Paddle for pipes:
Microswitch spring:
O-Ring seals:
Dimensions
drinking water and glycol solutions
50%
10 bar
-30–120°C
55°C
1” M
from 1” to 8”
A
B
250 V
15 (5) A
IP 54
CE
Code
626600
A
1"
B
63
C
86,5
D
134,5
E
74
F
Weight (Kg)
60,5
0,930
Operating principle
Construction details
The flow switch is composed of a blade (1) integral with a control
rod (2) connected, at the top, to an adjustable counter spring (3).
The assembly, by turning around a pin under the action of the water
flow, operates a microswitch contained in a protective casing (4). At
rest, the counter spring keeps the microswitch contact open. When
the increasing flow rate of the medium within the piping becomes
equal or greater than the trip flow rate, the thrust (5) on the blade
applied (1) by the flow overcomes the opposing force applied by
the adjustable spring (3) thus making the microswitch contact
close. With a decreasing flow rate, on reaching the trip flow rate
values, the flow thrust on the blade is not enough to overcome the
opposing force applied by the adjustable spring, so the blade
returns to the rest position and the microswitch contact opens.
The trip values for closing (increasing flow) and opening
(decreasing flow) the microswitch contact can be modified by
means of the adjusting screw (6).
Electric component protection
A metal bellows (7) separates the electric and the hydraulic parts.
Since this is the most stressed part that must prevent any contact
between the medium and the electric components, it is made of
stainless steel. Stainless steel is moreover used in the construction
of other mechanical components as well so as to make them
immune from corrosion.
Electric switchover contact
The electric switchover contact indistinctly permits turning on or off
any electric device at the trip flow rate.
4
6
3
8
Insulating protective cover
The O-Ring seal (8) between the body and the cover,
with a protection class of IP 54, ensures operation in particularly
damp and dusty places. The insulating protective casing (4) on the
microswitch avoids the risk of accidental contact when calibrating.
Both the microswitch protection and the cover are made of
self-extinguishing V-0 class plastic.
8
Setting screw
The setting screw (6) allows easy adjustment of the trip flow rate as
desired.
7
2
5
1
Certification
The water flow switch 626 series is made by Caleffi S.p.A. in
compliance with the essential safety requirements of directive
89/336/EC and 72/23/EC of the European Parliament and Council of
the European Union.
Hydraulic characteristics
Δp (kPa)
Δp (mm w.g.)
1"
1 1/2"
2 1/2"
900
800
700
9
8
600
450
400
4,5
4
350
3,5
300
3
250
2,5
180
160
140
1,8
1,6
1,4
120
1,2
6"
8"
10
9
8
7
900
800
700
6
600
6
450
400
4,5
4
350
3,5
300
3
250
2,5
180
160
140
1,8
1,6
1,4
120
1,2
0,9
0,8
5
500
2
200
1
100
7
5
2
1
0,7
90
80
70
60
0,6
60
0,6
45
40
0,45
0,40
0,5
0,45
45
40
50
0,40
0,7
0,5
35
0,35
35
0,35
30
0,30
30
0,30
25
0,25
25
0,25
18
16
14
0,18
0,16
0,14
12
0,12
1”
10
1 1/4”
21
1 1/2”
32,5
2”
58
0,1
1000
G (m3/h)
Size
Kv* (m3/h)
600
700
800
900
500
250
300
350
400
450
200
120
140
160
180
60
70
80
90
100
50
25
30
35
40
45
20
12
14
16
18
10
7
8
9
16
18
20
14
12
8
9
10
7
6
4
4,5
5
3
3,5
2,5
1,8
1,6
2
1,4
1,2
0,8
0,9
1
0,2
0,7
0,1
10
0,12
6
12
10
0,2
3,5
4
4,5
0,18
0,16
0,14
5
14
18
16
20
2,5
3
0,2
0,6
20
1000
4"
0,9
0,8
0,5
50
10
3"
90
80
70
0,35
0,40
0,45
100
0,30
200
0,25
500
Δp (kPa)
Δp (mm w.g.)
2"
2
1000
1 1/4"
G (m3/h)
Size
Kv* (m3/h)
2 1/2”
120
3”
180
4”
350
6”
950
8”
1950
*The stated Kv values refer to the head loss within the pipes with diameters from 1” to 8” and standard length of 1 m, in which flow switches,
equipped with a blade of adequate size, are installed.
Reference standards
Setting
In heating systems with a closed expansion tank, where circulation
is ensured by motor pumps, the flow switch must be used to stop
the heat supply to the generator when the pumps stop and there is
no circulation.
The setting is made by turning the screw (1) clockwise to close the
contacts at higher flow rates or anticlockwise for lower values.
Water circulation is indeed essential for safety and
temperature-sensitive protection devices such as thermostats,
thermal discharge valves and fuel shut-off valves to work properly.
After making the adjustment, lock the setting screw with the ring nut (2).
The operator is protected against accidental contact with electrical
parts of the flow switch by an insulating protective cover (3) on the
microswitch.
3
2
1
Installation
The unit is equipped with a set of blades (1), to be used for different
pipe diameters, particularly sized to allow easy installation and
minimal head losses.
For diameters equal to or greater than 3” (DN 80), it is necessary to
add to the preassembled blades in increasing order the long blade
(2) (supplied in the package), just cutting it to the size
corresponding to the desired diameter.
Outline of the microswitch connections:
Flow switch used to turn on a device with no flow
LINE
1
COM.
3
N/O
2
N/C
INLET
3"-DN 80
Flow switch used to turn on a device with flow
LINE
4"-DN100
1
COM.
5"-DN125
2
1
1"
6"-DN150
1
1
2"
DN175
2
3
N/O
2
N/C
8"-DN200
INLET
2 1/2”
3”
4”
1,3
1,7
2,6
3
5
6,8
10 16,5 37
with
decreasing
flow
0,9 1,25 1,9
2,2
3,7
5,2
8,5 14,5 33
with
increasing
flow
2,8 3,8
5,9
6,7 11,7 15,8 21,5 43
76
with
decreasing
flow
2,7 3,7
5,8
6,6 11,5 15,6 21
70
FACTORY
SETTING
20 mm
80 mm
MAXIMUM
SETTING
36
8”
2”
with
increasing
flow
Diameter
pipe
6”
1 1/2”
1 1/4”
Trip flow rate (m3/h) for horizontal installation*
When the trip flow rate is reached or exceeded with an increasing
flow, contacts 1 and 3 of the microswitch close, while contacts 1
and 2 open.
On the contrary, when the trip flow rate is reached with a
decreasing flow, contacts 1 and 2 close.
1”
The flow switch should preferably be installed on the pipe with the
control rod upright, respecting the flow direction indicated by the
arrow on the cover and on the body exterior.
For blade proper operation it is necessary to install the flow switch
by respecting the distance shown on the drawing, using a sleeve
welded for total passage.
*For vertical installations, it is necessary to use the setting screw (1)
to identify the optimal trip point.
Application diagrams
Example of using the flow switch in a plumbing system
In systems for instantaneous hot water production with heat exchangers, the flow switch has the job of governing the pump and enabling water
circulation in the exchanger primary circuit when required by the user.
Instantaneous production of hot water
Mixed production of hot water
C F
C
R
F
T
Tmax
Shut-off valve
Pressure reducing valve
Mixing valve
Pump
Check valve
Autoflow
Example of flow switch use in a refrigerating system or heat
pump
The flow switch is useful on machinery in general where water
circulation is considered essential for the equipment to work
properly.
A typical example is the chiller unit shown in the figure.
CHILLER UNIT / HEAT PUMP
COMPRESSOR
The two flow switches trip to stop the compressor from working if
one of the following conditions occurs:
- insufficient or no flow of cooling water in the condenser (danger
of overheating)
- insufficient or no flow of refrigerated water (danger of ice forming
on the evaporator and liquid returning to the compressor suction
side).
SECONDARY
CONDENSER
CONDENSER
EXPANSION
VALVE
EVAPORATOR
SECONDARY
EVAPORATOR
SPECIFICATION SUMMARIES
626 series
Flow switch. 1” M connection. CE certificate in accordance with directives 89/336 EC and 72/23 EC. Brass body.
Self-extinguishing polycarbonate cover and microswitch protection casing. Stainless steel bellows and bellows rod, paddles
for pipes and microswitch spring. EPDM O-Ring seals. Maximum working pressure 10 bar. Medium temperature range
-30–120°C. Maximum ambient temperature 55°C. Medium drinking water and glycol solutions; Maximum percentage of glycol
50%. Voltage 250 V. Current 15 (5) A. Protection class IP 54. Pipes adjustability from 1” to 8”.
We reserve the right to change our products and their relevant technical data, contained in this publication, at any time and without prior notice.
CALEFFI
CALEFFI S.P.A. · I · 28010 FONTANETO D’AGOGNA (NO) · S.R. 229, N.25 · TEL. +39 0322 8491 R.A. · FAX +39 0322 863723
· www.caleffi.com · [email protected] ·
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